Clariant, Haltermann, and Mercedes-Benz are launching a fleet test in Germany using cellulosic ethanol produced by the Clariant sunliquid process using wheat straw as the feedstock. Haltermann mixes the cellulosic ethanol with conventional fuel components to form the new sunliquid20 E20 (20% ethanol) fuel. The fuel features a high octane number (RON) of more than 100.

Over the next twelve months, test fleet vehicles will be refilled with the new fuel at a specially equipped gas station on the Mercedes-Benz site in Stuttgart-Untertürkheim. The cellulosic ethanol comes from Clariant’s sunliquid demonstration plant in Straubing, where approximately 4,500 tons of agricultural residues such as grain straw or corn stover are converted into cellulosic ethanol each year. Haltermann blends the ethanol with gasoline at its plant in Hamburg.

Mercedes-Benz fleet at Clariant’s sunliquid demonstration plant for production of cellulosic ethanol from agricultural residues. (Photos: Clariant/Rötzer.) Click to enlarge.

During the fully integrated sunliquid process, highly optimized, feedstock-specific biocatalysts split cellulose and hemicellulose into fermentable sugars with high yields under stable process conditions. The process-integrated production of biocatalysts offers flexibility and reduces production costs.

In the next step, an optimized fermentation organism allows both C5 and C6 sugars to be converted into ethanol, thus increasing the ethanol yield by around 50%. A novel purification process developed by Clariant is instrumental in enabling all the energy required for the process to be derived from the insoluble residue lignin.

The resulting cellulosic ethanol saves around 95% of CO2 emissions when compared to fossil gasoline.

Since July 2012, Clariant has been operating a demonstration plant in Straubing, which produces up to 1,000 metric tons of cellulosic ethanol from around 4,500 metric tons of raw material every year. The total volume of the project in Straubing amounts to around €28 million (US$38 million), comprising investment of around €16 million (US$22 million) and concomitant research of nearly €12 million (US$16 million). The Bavarian government and the German Federal Ministry of Education and Research (BMBF) each contributed around €5 million (US$7 million) to this and other related research projects.

Cellulosic ethanol is a genuinely sustainable and advanced biofuel of the latest generation. It is produced in Germany from agricultural residues. The fleet test will demonstrate that the fuel is ready for market and technically compatible with in series vehicles at a blending rate of 20% with super gasoline. This shows that second generation biofuels based on agricultural residues are now technologically ready and available, not only in production but in application as well.

—Professor Andre Koltermann, Head of Group Biotechnology at Clariant

Our main task is to shape solutions for sustainable mobility of the future. We see great potential in second generation biofuels with regards to sustainability and reduction of greenhouse gases. Petrol with 20% ethanol can already be used easily in our latest Mercedes-Benz BlueDIRECT petrol engines. This offers ideal potential for best efficiency and high greenhouse gas savings.